Design and Evolution of Metal-Based Functions in Supramolecular Protein Scaffolds

金属蛋白具有许多对生物学和人类健康至关重要的细胞功能。而我们的 由于技术的进步，对金属蛋白功能的了解已经大大增加，我们仍然 对蛋白质结构/动力学与金属之间的相互作用仅有肤浅的了解 协调性/反应性因此，还不可能a)预测其作用机制 金属蛋白质只通过观察它们的结构，b)模仿或改进结构和功能 通过从头设计，以及c)了解复杂的生物无机功能可能具有 在自然进化过程中出现在简单的多肽/蛋白质支架上。建议的总体目标是 研究计划是通过设计和构建蛋白质支架来应对这三个挑战 从零开始，越来越复杂的基于金属的功能。灵感来自于一条假设的自然之路 金属蛋白的进化，我们最近开发了金属蛋白设计的新方法，其中 单体蛋白质以金属离子为模板，形成新颖的超分子组装。的接口 这些进化上天真的复合体随后被设计和进化以产生独立的蛋白质 具有复杂的基于金属的功能的架构。在拟议的研究中，我们将进一步发展这些 利用我们实验室开发的两种新型蛋白质支架的“金属模板化蛋白质设计”策略 (DiCyt和TriCyt)，它们提供了对不同金属配位几何图形的轻松访问，次级球体 环境和全局属性(可调结构、低聚状态、灵活性/刚性)很难 与其他蛋白质设计策略相结合。我们将使用DiCyt和TriCyt支架构建金属蛋白 用于稳定和选择性配位第一排过渡金属离子的组件(特定目标1)，用于挑战 酯、酰胺和磷酸酯键的水解反应(特定目标2)，以及氧化还原催化反应 涉及氧结合和活化(具体目标3)。这些努力不仅将揭示根本 结构-功能关系，管理不同的金属蛋白活性，但也导致更好的理解 生物无机复杂性如何出现在简单的蛋白质支架中。

Metalloproteins carry out many cellular functions that are central to biology and human health. While our knowledge of how metalloproteins function has grown immensely thanks to technological advances, we still possess only a superficial understanding of the interplay between protein structure/dynamics and metal coordination/reactivity. As a result, it has not yet been possible a) to predict the functional mechanism of metalloproteins simply by looking at their structures, b) to emulate or improve upon the structures and functions of metalloproteins by de novo design, and c) to understand how complex bioinorganic functions may have emerged on simple peptide/protein scaffolds during natural evolution. The overarching goal of the proposed research program is to address these three challenges by designing and constructing protein scaffolds with increasingly more complex metal-based functions from scratch. Inspired by a hypothetical pathway for the natural evolution of metalloproteins, we have recently developed new approaches to metalloprotein design in which monomeric proteins are templated by metal ions to form novel supramolecular assemblies. The interfaces of these evolutionarily naïve complexes are then engineered and evolved to create self-standing protein architectures with complex metal-based functions. In the proposed research, we will further develop these “metal-templated protein design” strategies by capitalizing on two new protein scaffolds developed in our lab (DiCyt and TriCyt), which provide easy access to diverse metal coordination geometries, secondary-sphere environments and global properties (tunable structures, oligomeric states, flexibility/rigidity) that are difficult to attain with other protein design strategies. We will use DiCyt and TriCyt scaffolds to build metalloprotein assemblies for stable and selective coordination of first-row transition metal ions (Specific Aim 1), for challenging ester, amide and phospho-ester bond hydrolysis reactions (Specific Aim 2), and for redox catalytic reactions involving dioxygen binding and activation (Specific Aim 3). These efforts will not only uncover fundamental structure-function relationships that govern diverse metalloprotein activities, but also lead to better understanding of how bioinorganic complexity emerges in simple protein scaffolds.